Satellites are sometimes used to relay communications around the world and/or to communicate with various airborne or remotely located vehicles, structures, or networks. For example, some military vehicles and/or posts use satellite transceivers to communicate with military networks. As such, an unmanned vehicle may be piloted and/or controlled via satellite links with the unmanned vehicle. To enable these and other satellite communications, communications satellites are used to route various communication streams around the world and/or among a constellation of communications satellites.
In some implementations, communications satellites have a switch that allows any satellite to connect to any other satellite beam in a configurable manner. Switches that perform subchannel filtering at the switch input and subchannel combining at the switch output are referred to in some embodiments as a “channelizer.” The channelizer functions by providing a collection of input paths that can be cross-connected to a collection of output paths to route subchannel information content in response to a cross-connection request.
Switch fabrics (or channelizers) may employ internal speedup factors or internal switching stages in order to mitigate the effects of blocking. As used herein, “blocking” refers to a state in which the fabric or channelizer operates in which sufficient inputs and outputs are, in theory, available, but an incoming cross-connection request cannot be accommodated by the channelizer. Switch fabrics (or channelizers) may be designed to be “strictly non-blocking” if the design contains sufficient internal speedup and/or internal switching stages and ports. A strictly non-blocking switch will never experience blocking conditions. Conversely, a switch fabric may be designed to be “rearrangeably non-blocking” where cross-connects through the switch fabric are dynamically rearranged by a control algorithm in order to eliminate or minimize blocking. Unfortunately, designing extremely high capacity strictly non-blocking channelizers is beyond the capability of current space-qualified ASIC technology. Further, the complexity and operational delays associated with dynamically reprogramming the subchannel filters and combiners in a channelizer render a rearrangeably non-blocking channelizer design moot. As such, extremely high capacity (i.e. terabit scale) channelizer designs are inherently blocking and intelligent control algorithms are required to mitigate the effects of blocking.
In some embodiments, the channelizer is controlled by an algorithm for accommodating incoming cross-connection requests. According to various implementations, the algorithm used to control the channelizer is a “first fit increasing” bin-packing algorithm. This algorithm actually leads to a blocking condition in the theoretically fasted possible manner. As such, cross-connection requests may be denied and the satellite may fail to provide communications when requested and/or required even though the channelizer fabric is very lightly utilized.
It is with respect to these and other considerations that the disclosure made herein is presented.